Add --no-background-compilation to tests that expect to run code in optimized form

tests/lib/typed_data/float32x4_cross_test.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
-// VMOptions=--optimization-counter-threshold=10
+// VMOptions=--optimization-counter-threshold=10 --no-background-compilation
 
 // Library tag to be able to run in html test framework.
 library float32x4_cross_test;
 
 import 'dart:typed_data';
 import 'package:expect/expect.dart';
 
 Float32x4 cross(Float32x4 a, Float32x4 b) {
   var t0 = a.shuffle(Float32x4.YZXW);
   var t1 = b.shuffle(Float32x4.ZXYW);
@@ skipping 26 matching lines @@
     testCross(x, z, -y);
     testCross(y, x, -z);
     testCross(x, x, zero);
     testCross(y, y, zero);
     testCross(z, z, zero);
     testCross(x, y, cross(-y, x));
     testCross(x, y+z, cross(x, y) + cross(x, z));
   }
 }